Blue anthraquinone dye.



UNITED STATES Patented July 12, 1904.

ATENT FFIQEJ.

IVILHELM BEROHELMANN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFABRIKEN OF ELBERFELD 00., OF NEWV YORK, N. Y., A

CORPORATION OF NEIV YORK.

BLUE ANTHRAQUINONE DYE.

SPECIFICATION forming part of Letters Patent No. 764,837, dated July 12, 1904.

Application filed January 27, 1904.

To all 1072 0772, it may concern.-

Be it known that L WVILHELM BERCHEL- MANN,doctor of philosophy, chemist,(assignor to the FARB ENFABRIKEN or ELBERFELD OoM- PANY, of New York,) residing at Elberfcld, Germany, have invented a new and useful Improvement in Blue Anthraquinone Dyestuffs; and I hereby declare the following to be a clear and exact description of my invention.

My invention relates to the manufacture of new blue dyestuffs of the anthraquinone series, being sulfonic acids of methylamidoalphylamido beta methylanthraquinone, having most probably the following general formula:

co I CH3 oan NH-orn (1) co NHR (4) (R meaning in this formula an alphyl radical, such as phenyl, tolyl, xylyl, or the like.) The said anthraquinone derivatives can be obtained, for instance, by first treating methylamido-beta-methylanthraquinone (obtainable from mononitro beta methylanthraquinone and methylamin) with bromin; secondly, condensing the resulting monobromo methylamido-beta-methylanthraquinone with aromatic amins-such as anilin, paratoluidin, xylidin, or the like-and finally treating the methylamidoalphylamido-beta-methylanthraquinones thus obtained with sulfonating agents. The new dyestuff sulfonic acids thus produced are in the shape of their alkaline salts dark powders soluble in water with a blue color. They dye unmordanted wool from acidbaths blue shades.

In order to prepare the new dyestuffs, I can proceed as follows, the parts being by Weight: Eight parts of bromin are slowly introduced into a mixture of ten parts of the above-mentioned methylamido beta methylanthraquinone in sixty parts of pyridin while stirring. The reaction mass is then heated for some time on the water-bath. On cooling, the brominated compound separates from the liquid in the shape of brownish-red crystals, being insolu- Serial No. 190,873. (No specimens.)

ble in water and soluble in pyridin and chloroform with a yellowish-red color.

In order to produce the condensation product with paratoluidin, ten parts of mono* bromomethyl amido beta methylanthraquinone are mixed with one hundred parts of paratoluidin and five parts of anhydrous sodium acetate. This mixture is boiled in a vessel provided with a reflux condenser until it has assumed a clear greenish-blue color which is not changed by further heating. After the reaction .mass has been allowed to cool down to about centigrade it is mixed with alcohol, by means of which operation the condensation product separates on cooling in the shape of crystals. For the same purpose the melt can also be poured into an excess of dilute hydrochloric acid. It is filtered off, washed with water, and dried.- By recrystallization from pyridin the new compound is obtained in the shape of dark crystals having a metallic luster, which are Soluble in pyridin and chloroform with a greenish blue and in glacial acetic acid with a violet-blue color turning bluish red by the addition of concentrated hydrochloric acid. In order to transform this condensation product into the new dyestuff sulfonic acid, ten parts of the finely-pulverized compound are stirred into one hundred parts of sulfuric monohydrate. The resulting solution is then heated to about from 7 O to v8O centigrade until a test portion is clearly dissolved by water on the addition of an excess of ammonia. The sulfonation can be carried out in a shorter time and at a lower temperature on adding slowly to the reaction mass a small quantity of fuming sulfuric acid. Subsequently the reaction mass is poured into about one thousand parts of water, by which means the new dyestulf sulfonic acid, which is very difficultly soluble in dilute acids, is precipitated. It is filtered ofif, washed with a small quantity of cold water, mixed with an excess of ammonia, and dried. IV hen dry and pulverized, the new coloring-matter is in the shape of the ammonium salt thus obtained a darkblue powder which is soluble in cold and more soluble in hot water with a blue color. It is nearly insoluble in absolute alcohol and in chloroform and soluble in hot pyridin with a greenish-blue color. By the addition of hy drochlorio acid to its aqueous solution the color of the latter turns red, and by the addition of ammonia to this acid solution the original blue color is again produced. By concentrated sulfuric acid (of 66 Baum) it is dissolved with a violet color. It dyes unmordanted wool from acid-baths blue shades. Having now described my invention and in what manner the same is to be performed, what 1 claim as new, and desire to secure by Letters Patent, is-

1. The herein-described new dyestuffs, being sulfonic acids of methylamidoalphylamido beta methylanthraquinones, which dyestuffs, in the shape of their alkaline salts,

I are dark powders soluble in water with a blue color, and dyeing unmordanted wool from acidbaths blue shades, substantially as hereinbe- 4 fore described.

2. The herein-described new dyestuff, being the sulfonic acid of methylamido-paratolylamido-beta-methylanthraquinone, which dyestuif is, in the shape of its ammonium salt, when dry and pulverized, a dark-blue powder being soluble in cold and more soluble in hot water with a blue color, being nearly insoluble in absolute ethyl alcohol and chloroform and being soluble in hot pyridin with a greenish-blue color; the color of its aqueous solution turning red by the addition of hy- 

